1. Field of the Invention
This invention relates to improvements in freight vehicles having a cargo space convertible for handling piece goods or bulk granular, powder or flake material.
2. Prior Art
The desirability of having the cargo space of a freight vehicle which would be suitable for handling either piece goods or bulk goods is well known. The obvious advantage is that the same cargo space on the same vehicle could handle either of these two significantly different types of loads. Convertibility of cargo space provides extreme flexibility and prevents empty runs of the vehicle. For example, a truck-trailer could handle piece goods such as palletized bags of sugar on one run and on a return run could handle bulk goods such as sugar in the bulk going back to the packaging factory; a plastics company could send finished goods in standard cargo space and return with a bulk load of resin; a brewer could send kegs or cases of beer and bring back malt or grains in the same vehicle, and there are many other uses of a similar nature.
The term "freight vehicle" encompasses any vehicle which could contain freight or cargo, including without limitation trucks, truck-trailers, railway cars, and movable containers such as are transported by ship, aircraft, truck and rail, as well as intermodal vehicles. "Piece goods" includes any individual item such as packaged or palletized goods commonly handled as individual pieces. "Bulk goods" includes any of the known and commonly shipped bulk granular or powder material.
Various convertible freight vehicles are already known; however, the known types all have certain disadvantages. For example, a van sold by Converta-Vans, Inc. of Wescoville, Pa. provides a cargo space with four separate convertible bulk hoppers utilizing gravity discharge from the hoppers and hinged floor sections above the hoppers. These hoppers make the van expensive and heavy, and the weight contributes to the energy expenditure of hauling. Moreover, general cargo vans are not easily converted to the Converta-Van configuration due to the necessity of providing the hoppers.
There also exists patented prior art on convertible freight vehicles, including U.S. Pat. No. 4,092,051, granted May 30, 1978. This patent similarly uses hoppers at the bottom of the bulk cargo space to assist in providing complete gravity discharge. The disadvantages of this hopper-containing vehicle are substantially the same as those of the Converta-Van product.
In U.S. Pat. No. 4,241,947, granted Dec. 30, 1980, there is shown a collapsible bulk storage member with slatted sidewalls, but it also has a fixed hopper-shaped bottom discharge. It is also subject to the same limitations as are present in the Converta-Van.
Thus, there is a need in the art to provide a simple, lightweight and inexpensive convertible cargo space in a freight vehicle which does not use hopper bottoms and which can be applied to conventional and existing freight vehicles with a minimum of modifications. This invention satisfies such need.
It is also known in the art to provide stationary bins for discharging free-flowing granular material which do not use hopper bottoms. See, e.g., British Patent No. 1,144,162. However, such stationary units are not suitable or practical for converting piece goods cargo space to handle bulk goods.